/*
 * The MIT License
 * 
 * Copyright (c) 2008 Comcast Interactive Media
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package cim.sf.core.command;

/**
 * A command that can be invoked by a console implementation.
 * <p>
 * Each command has a unique path. This helps to organize commands
 * into related groups.  E.g., ContentService commands might all
 * live under the <code>/cs</code> path, consisting of, for example,
 * <ul>
 * <li>/cs/view</li>
 * <li>/cs/delete</li>
 * <li>/cs/list</li>
 * </ul>
 * <p>
 * Each command must have an associated path, and the path must be unique.
 * A command may also have an associated description, and a list of possible
 * usage scenarios. 
 * 
 * @author <a href="mailto:jeremy_volkman@cable.comcast.com">Jeremy Volkman</a>
 *
 */
public interface Command {

    /**
     * Returned when a Command throws an InvalidUsageException
     */
    public static final int ERROR_USAGE = 64;
    
    /**
     * Returned if a Command throws any other exception, or if some
     * other error occurs.
     */
    public static final int ERROR_GENERAL = 1;

    /**
     * The command path. E.g., "/useradmin/adduser"
     * @return The command's path
     */
    public String getPath();
    
    /**
     * Command usages, which may be <code>null</code>.
     * @return Command usages.
     */
    public String[] getUsage();
    
    /**
     * Command description, which may be <code>null</code>.
     * @return Command usages.
     */
    public String getDescription();
    
    /**
     * Execute the command.
     * @param ci The <code>{@link CommandInvocation}</code> object associated with
     * this invocation of the command.
     * @return An exit status code
     * 
     * @throws InvalidUsageException if the given command arguments are invalid.
     */
    public int execute(CommandInvocation ci) throws InvalidUsageException;
}
